I agree that the Quectel EM06-E looks very promising and as @36w4r6 informed me there is from Quectel already available cheaper (without embedded GNSS) solution: EM05-E that eventually might be as well adequate and good solution for B28 Librem 5 users … if happens that the Librem 5 comes out without LTE Band 28 coverage.
Librem 5 antenna should be suitable (without some limitations) for usage at lower frequency range: 703 – 748 MHz for uplink and 758 – 803 MHz for downlink, isn’t it?
Cat 4 v Cat 6 though i.e. 150Mbps download v. 300Mbps download. In terms of the lifecycle of the module it might be better to have that headroom. It wouldn’t make any practical difference to metoday however i.e. in terms of what I could download with LTE right now.
As showed with Antenova’s Cat4 LTE Development Kit both of above to be usable on B28 need supportive antenna like Antenova Twin LTE Diversity Antennas: SR4L034-L / SR4L034-R “Inversa”. This was my partial point.
Wow, that is price gouging! The Pinephone has the Quectel EG-25G and the whole phone only costs $150. I bet PINE64 isn’t paying more than $15 for the chip. Putting a chip on an M.2 card doesn’t cost that much. Hopefully other manufacturers will appear.
A worldwide chip like the Quectel EG-25G probably costs a dollar or two more than a chip like Quectel EM05 and probably a dollar or two less than the EM06. Considering that PINE64 is manufacturing in small quantities, 4GLTE probably is getting the same kind of bulk pricing on a couple thousand chips at a time. Yes, engineering an M.2 card and fabrication costs something, but I bet that 4GLTE is making over $100 in profit on each M.2 card it sells.
Also consider the fact that UNISOC and MediaTek sell low-end SoCs with integrated cellular modems for $4-5 per chip. Yes, the Quectel chips have an extra heat spreader and come in a more expensive package, but Quectel is charging a lot more than it charges to integrate the same modem in an ASIC, and then 4GLTE is charging a huge amount more just to mount that same chip on a M.2 card.
So first the Quectel EG-25G is a miniPCIe form factor card, we are looking for an M.2 card. The M.2 spec is a little different - smaller and less power consuming.
Then also if you look at other modem please look carefully if they also support voice and if yes, how they do it. Last year when we started doing research there were almost no ready-made M.2 modem cards available that supported voice - but for a phone I guess this is an important feature?
Lastly when you look at bare chips please do not forget that you can not simply 1:1 compare a complete pre-qualified modem module with the bare chips. There is a lot more to go into a modem module than just the silicon parts - like the bespoken qualification, testing and not to forget patent licenses. The 3GPP 4G patents are way over a thousand from several hundred patent holders. A huge amount of money from the modem module price goes into these licenses. The basic rule of thumb is to set aside about 20% of the sales price of a cellular device for patent royalties.
The cellular market is a battle field full of booby traps.